An American compromise proposal to break the Egyptian-Israeli negotiating impasse received a serious setback yesterday as Egypt's vice president arrived in Washington carrying a negotiating proposal that Israel is unlikely to accept, informed sources said.

Vice President Hosni Mobarak is expected to propose to President Carter at a White House meeting today that the U.S. plan for commitments to elections on the West Bank be shelved in favor of immediate Egyptian-Israeli negotiations on the Gaza Strip, according to these sources, who are aware of Egyptian thinking on the issue.

Egpytian officials stressed that President Anwar Sadat is putting forward the proposal to begin discussion of future Palestinian rights with the formerly Egyptian-occupied Gaza Strip rather than on the West Bank in an effort to facilitate rather than obstruct the month-old-negotiations, which have reached a virtual deadlock over the issue of formally linking the Egypt-Israel pact to negotiations on the future of the West Bank and Gaza.

By trying in effect to finesse the American compromise proposal, which has also run into strong opposition in Israel, Sadat "seems to be doing something he thinks is helpful," one U.S. official said yesterday, "but this hardly looks like a solution."

Israel's cabinet responded to reports of a new Sadat counterproposal by suspending debate on the U.S. compromise plan, given by Secretary of State Cyrus Vance to Prime Minister Menachem Begin Sunday in New York.

In Washington, Israeli officials reportedly were deeply concerned about the prospect that Sadat was putting forward new demands at the last minute of the complex negotiations. Begin faces strong opposition within his cabinet to any formal linkage of the treaty and the future status of the West Bank.

The prime minister is known to have expressed strong reservations to Vance about some points in the compromise proposal, but to have told the secretary that the plan was a base for continuing discussions.

Sadat surfaced the idea of moving from the signing of the Egyptian-Israeli treaty directly to discussing the status of the Gaza Strip - a tiny, crowded enclave where more than 400,000 Palestinians live - during a private talk with Egyptians politicians in Ismalia Tuesday. But reports of what he said have been fragmentary and second-hand.

Egypt ruled the Gaza Strip from 1948 until Israel's 1967 occupation. On several previous occasions, Sadat has raised the possibility that because of the historical tie, he alone could negotiate self-rule for the Palestinians in the Gaza Strip in order to set a precedent for the West Bank territory, which was ruled by Jordan until 1967.

The main advantage of such an arrangement would appear to be bypassing Jordan's King Hussein and West Bank Palestinian leaders if they refused to participate in the three-year negotiations with Israel called for in the Camp David framework agreement on the West Bank. The recent Baghdad conference of Arab leaders called on Hussein and the Palestinians to refuse to enter such negotiations.

Sadat was reported by Arab sources yesterday to have been more deeply concerned about the outcome of the Baghdad meeting than he has indicated in public.

Because of his previous references to such a possibility. Egyptian and U.S. officials assert that Sadat has not sent a "new" proposal to Carter with Mobarak, but rather is bringing forward an idea that has always been on the table, now that the U.S. compromise seems to have bogged down.

But conference sources said that both the Egyptian and Israel delegations have become gravely concerned this week by what appears to be a new round of miscalculations and misreadings of motivations by each side during the past week. The Israelis are particularly puzzled by Sadat's tactics in bringing to the surface the Gaza idea and offering to bypass the West Bank for the time being after the Carter administration had spent a great deal of diplomatic capital on the West Bank linkage issue.

Defense Minister Ezer Weizman met with Carter for about an hour late Tuesday and then reportedly relayed a request to the Israeli cabinet to delay consideration of the U.S. proposal until after Mobarak's visit.

In another development, the Norwegian Nobel Committee announced that both Begin and Sadat will go to Oslo Dec. 10 to share the Nobel peace prize.U.S. officials said Carter does not plan to meet with the two leaders again until the treaty signing.