Most Jews do not accept Jesus as the Messiah who comes twice. Scripture doesn't say He'll come twice; it doesn't say He comes once to do it all. It is undefined enough so God can share salvation with the gentiles, while the Jews are blinded (as Marianne stated). That does not mean they are lost.
The question is better for discussing than answering....
The first hurdle is that the mainstream Christian denominations are quite Judeophobic - so you get a biased response from most Christians.
The other major problem from Christians to answer this question is that they are hung-up on the name, "J-e-s-u-s." The Messiah who lived 2000 years ago was not known as "Jesus" - no one called Him that, no one referred to Him like that. Why? There is no "J" in Hebrew or Aramaic. "Jesus" is a Westernized creation. His name is Yeshua, which means "God saves," "salvation," or "savior" - "She will give birth to a son, and you are to name him Yeshua, [which means `ADONAI saves,'] because he will save his people from their sins." - Matthew 1:21 (The Complete Jewish Bible).
Another issue for most Christians is that God did not forsake Israel or the Israelites/Jews; God did not replace Israel with the "Christian Church." And probably most important, God has one plan of salvation for people - the faithful - His people. Abraham was deemed righteous (and saved) because of his faith - all of the OT patriarchs & faithful believers were saved by the Grace of God because they believed that God would send His Salvation ["Yeshua"] to save them. How are faithful believers saved today? By the Grace of God because they believe in Jesus, Yeshua, God's salvation. What's the difference? (That's a rhetorical question - tear the uninspired pages <i.e. "Old Testament" title page & "New Testament" title page> out of your Bibles - God never intended for there to be a separation in His Scripture - it is a man-made barrier to understanding Scripture, it is a man-made barrier to Truth, it is a man-made barrier to salvation.) There is no difference. The OT is the NT concealed; the NT is the OT revealed - they are the SAME Gospel message!
Now, back to the question: What about the Jews? Those who were faithful believers in God's salvation were saved in the OT; I believe that today they will be saved the same way - even if they don't use the word "Jesus" for God's salvation.
If you think "Jesus" is a ~magical~ name, check with your spiritual leader for clarification.